The present invention relates to an industrial robot system used in combination with a machine tool and the like.
The use of the industrial robot system in combination with a machine tool sometimes causes a dangerous state, such as a clash between the machine tool and the robot, and accordingly reduces the reliability of the industrial robot system, unless the robot is operated in accordance with the operating conditions of the machine tool. To prevent such dangers from occurring in the prior art industrial robot system, the action of the robot is controlled by such signals as WAIT signal, an INHIBIT signal and an EMERGENCY STOP signal which are produced in the machine tool.
However, these three kinds of signals, i.e., WAIT, INHIBIT and EMERGENCY STOP, are insufficient for dealing with all kinds of conditions for operating the machine tool, since there are so many kinds available. The most suitable manner for controlling a robot should be selected in accordance with various kinds of abnormal conditions of arising during the operation of the machine tool which is the function of the industrial robot system. With only these three kinds of signals, it is difficult to obtain the most suitable manner for controlling a robot.
The present invention was introduced because of the need to solve the above-described difficulty.
It should be noted that the above-mentioned prior art industrial robot system is disclosed, for example, in the Manual for Operation of the Industrial Robot System "UNIMATE", published by KAWASAKI HEAVY INDUSTRIES LTD.